Tube-mill.



1. s. FIASTING.

TUBE MILL.

APPLICATION FILED AUG-31, I9l6.

Patented Feb. 25, 1919.

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' ATT$RNEL$ To all whom it may concern:

JOHA'N s. FASTING, 0E FREDERIKSBERG, NEAR coPENHnoEN, DENMARK, ASSIGNOBT0 F. L. smmm & 00., or NEw YORK, N. Y., A CORPORATION or NEW JERSEY.

T BE-MILE.

Specification of Letters Patent.

' Application filed August 81, 1916. Serial No. 117,854.

Be it known-that I, JoHAN S. FASTING, a subject of the King of Denmark,residing at Frederiksberg, near Copenhagen, Denmark, have inventedcertain new and useful Improvements in Tube-Mills, of which thefollowing is a specification, reference being had to the accompanyingdrawings, forming a part hereof.

In Letters Patent of the United States No. 1,204,554, dated November 14,1916, there is shown and described an improved method in the art ofgrinding with free grinding bodies which consists in producing in themill a slowly rotating mass of grinding bodies and material to be groundand applying closely-related frictional lifting ribshaving surfacesextending in the direction of rotation to said mass while rotating. Assuggested in the specification of said patent, the closely relatedlifting surfaces might have their gripping action accentuated byroughening the faces of the lifting ribs so as to increase the frictionbetween the ribs and, the material. The present application is concernedwith a grinding mill provided with frictional lifting ribs of thegeneral character claimed in said patent and seeks to cover,specifically, lifting ribs having roughened or corrugated faces or stepson such faces for the purpose of afl'ordin positive support to asubstantial portion 0 the mass between adjacent ribs and therebyincrease the lifting effect of the ribs partially by such positivesupport and partially by the increased frictional drag of the faces onthe charge. In practising the invention, the charge is separated intoparallel, circumferential streams by the annular partitions and eachstream is wedged between roximate ribs so that the charge therein willbe carried up the wall of the mill partially by the positive liftingaction of the irregular faces of the ribs and partially by the lateralsupport afforded by the frictional engagement of the charge with theribs. In accordance with the present invention the annular partitionsmay be formed in a number of difierent ways but aiford,.in eachembodiment,

partition constructed in accordance with the invention.

Figs. 48 are fragmentary detail views in sectlon taken through ribshaving roughened lifting surfaces in accordance with this invention andadaptable for use in any one of the mills shown in Figs. 1-3.

As pointed out in the preamble, the lIl lproved method of grinding setforth in the patent referred to consists in applying closely relatedfrictional liftin partitions on the inner wall of a mill, where y uponrotation of the mill these partitionswill separate the charge intoparallel circumferential streams and thereby add lateral support to thelifting action of the centrifugal force de rived from rotation of themill. The present invention contemplates the employment of the samemethod of grinding with free grinding bodies in that the charge isbroken up into parallel, circumferential streams by closely relatedannular partitions and support is given to each of these streams by thepartitions in order to supplement the lifting action of centrifugalforce derived from rota- ;tionof the mill.

In accordance with the present invention,however, mere lateral supportof the streams, such as would be derived from impressin frictionallifting surfaces on the sides 0 the streams, is not reliedupon entirely,but the surfaces of the annular partitions or ribs are formed of suchcross-sectional contour as to afford, to an appreciable degree, apositive support for a substantial portion of the charge within thestreams. The provision of such irregularly formed surfaces on theannularpartitions or ribs also insures a marked increase in the 10.5wedging action on the charge in each stream and a corresponding increasein the lateral support afforded to the charge through this wedgingaction. Iteis to be noted that whereverthe term partition is employed inthe specification and claims, it is intended to cover any elements,whether integral or sectional, whereby a dividing or partitioning actionis effected.

Referring now to the embodiments shown .in the accompanying drawings,which will serve to emphasize some of the forms of the presentinvention, it will be seen that in ig. 1, there is secured to the'innerwall of the mill a, a partition b made up of a serles of ribs or flanges0 which are secured to the inner wall of the mill and are spaced from-In Fig. 2 it will be seen that the partition B is made up as a singleintegral annular rib C of smaller diameter than the inner diameter ofthe mill and this rib is secured in place by lugs or feet e interposedbetween the rib and the wall of the mill at suitable intervals aroundthe periphery of the rib. By mounting the rib C in the 85 'there is anannular space D left between the rib and the lining of the mill for freelongitudinal movement of the material through the mill.

Still another form of partition E is shown in Fig. 3. This partition,like that shown in Fig. 2, is formed as an unbroken annular rib C ofsmaller diameter than the inner diameter of the mill. This integral .etrib is supported on a suitable spider f, the

radial arms of which are carried on a hub g keyed on-a suitablesupporting shaft h which may be mounted coaxially with the mill andextend th'erethrough. In this embodiment the parts are so dimensioned asto leave an annular space D between the inner lining of the mill and theouter periphery of'the rib C" which space is of the same generalcharacter as the space D shown in Flg. 2 and permits free longitudinalmovement of the material through the mill.

Thus far it has been sought only to discuss three of the many formswhich the partitions embodying the invention may as- 60 sume, in anendeavor to emphasize that the invention is not to be limited to theparticular means for forming these partitions or of mounting them in themill so as to perform their intended functions and yet permit freelongitudinal movement of the material manner described, it will beevident that.

through the mill. The invention, however, is primarily concerned withthe specific character of the ribs employed in the formation of thesepartitions since the character of the .partitions themselves differs inno wise'in this application from that contemplated in the original case.

In Figs. 48 there are illustrated in section, by way of example,fivedifi'erent forms of llbS which embody the present invention and maybe employed in the partitions shown in Figs. 1-3. The characteristicfeature of-th'ese ribs resides in the provision of radial shelves whichshall afford a positive lifting action for an appreciable part of themass inthe circumferential streams and incidentally increase appreciablythe lateral support given by the frictional drag impressed on the massby the rib. The rib is shown in Fig. 4 has annular 'groovesor 86corrugations it formed on its opposite faces, these grooves being ofsuch shape as to give positive support to. the material restin in thegrooves and impress on thev mass a rictional drag which shall serve toinsure a 90 wedging action suflicient to carry the charge part way upthe wall of the mill and to a point beyond where centrifugal force alonewould carry it. The shape of the grooves, however, it'will be noted, issuch as to perinit the charge to fall from the face of the ribimmediately upon the breaking down of the aforementioned Wedge or arch.

In principle, and general cross-sectional appearance, the constructionand operation of the ribs Z, on and 11. shown in Figs. 5-7,respectively, are very similar to the construction and action of the ribshown in Fig. 4. These ribs are grooved on their opposite faces topermit the charge to enter and be given appreciable positive support andbe subjected to an increased gripping action for the substantial lateralsupport desirable for the successful practice of the method.

The rib-0 shown in Fig. 8, while of somewhat difl'erent contour, isintended to function in the manner described in connection with theother ribs shown in the drawings. This rib is corrugated and its groovesinstead of being angular in cross-sectional outline are curved.

It will be understood that the positive support afforded by the ri-bsinaccordance wit the improvements may be varied through wide ranges bychanging the crosssectional contour of the grooves between one which ismost abrupt and angular, such as is suggested in Figs. 6 and 7 to onewith gently rounded grooves of the character suggested in Fig. 8.

As pointed out hereinbefore, the partitions in Figs. 1, 2 and 3 may bemade up either with unbroken ribs spaced from the wall of the mill ormay be formed with a circumferential series of short arcuate ribs 130(as in Fig. l) the primary functions of the partitions being preservedin either case and free longitudinal movement of the material.

through the mill being provided for. The partition itself may be formedof an unbroken rib or ribs of the character described in connection withthe several embodiments shownin Figs. 48, the supplemental posiing aperipheral lining and a diametric partition with its periphery adjacentsaid lining and having its opposite side forming radially extendingshelves.

2. A tube mill conslsting of a drum having therein a diametricalpartition Witha central opening, said partition formed of imperforatesections each of which has radial grooves in its opposite sides openinglongitudinally of the drum.

This specification signed this 9th day of May, A. D. 1916. JOHAN' s.FASTING.

